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authorJakub Kicinski <kuba@kernel.org>2023-10-27 15:34:08 -0700
committerJakub Kicinski <kuba@kernel.org>2023-11-01 22:14:00 -0700
commit2b7ac0c87d985c92e519995853c52b9649ea4b07 (patch)
treee15c0ce79a0e68cd9d9949663fefb302245f5d60 /tools
parent05f0431bb90f2ee3657e7fc2678f11a1f9b778b7 (diff)
tools: ynl-gen: don't touch the output file if content is the same
I often regenerate all YNL files in the tree to make sure they are in sync with the codegen and specs. Generator rewrites the files unconditionally, so since make looks at file modification time to decide what to rebuild - my next build takes longer. We already generate the code to a tempfile most of the time, only overwrite the target when we have to. Before: $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:19:56.347071940 -0700 Modify: 2023-10-27 15:19:45.089000900 -0700 Change: 2023-10-27 15:19:45.089000900 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 $ ./tools/net/ynl/ynl-regen.sh -f [...] $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:19:56.347071940 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 After: $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:22:41.520114221 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 $ ./tools/net/ynl/ynl-regen.sh -f [...] $ stat include/uapi/linux/netdev.h File: include/uapi/linux/netdev.h Size: 2307 Blocks: 8 IO Block: 4096 regular file Access: 2023-10-27 15:22:41.520114221 -0700 Modify: 2023-10-27 15:22:18.417968446 -0700 Change: 2023-10-27 15:22:18.417968446 -0700 Birth: 2023-10-27 15:19:45.088000894 -0700 Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/20231027223408.1865704-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'tools')
-rwxr-xr-xtools/net/ynl/ynl-gen-c.py7
1 files changed, 6 insertions, 1 deletions
diff --git a/tools/net/ynl/ynl-gen-c.py b/tools/net/ynl/ynl-gen-c.py
index 13427436bfb7..c4003a83cd5d 100755
--- a/tools/net/ynl/ynl-gen-c.py
+++ b/tools/net/ynl/ynl-gen-c.py
@@ -3,6 +3,7 @@
import argparse
import collections
+import filecmp
import os
import re
import shutil
@@ -1168,7 +1169,7 @@ class CodeWriter:
if out_file is None:
self._out = os.sys.stdout
else:
- self._out = tempfile.TemporaryFile('w+')
+ self._out = tempfile.NamedTemporaryFile('w+')
self._out_file = out_file
def __del__(self):
@@ -1177,6 +1178,10 @@ class CodeWriter:
def close_out_file(self):
if self._out == os.sys.stdout:
return
+ # Avoid modifying the file if contents didn't change
+ self._out.flush()
+ if os.path.isfile(self._out_file) and filecmp.cmp(self._out.name, self._out_file, shallow=False):
+ return
with open(self._out_file, 'w+') as out_file:
self._out.seek(0)
shutil.copyfileobj(self._out, out_file)